Method of producing pill resistant polyester fiber containing fabrics



United States Patent M ABSTRACT OF THE DISCLOSURE A method of producingpill resistant fabrics from polyester fiber containing blended yarnscomprising restraining the fabric and then heating the restrained fabricwhereby the polyester fiber components shrink and migrate to the centerof the yarns making up the fabric.

This invention, which is a divisional application of copendingapplication Ser. No. 371,768 filed June 1, 1964, now abandoned, relatesto the production of pill-free, soft, brushed polyester/cellulosic andpolyester/wool blend fabrics.

Fabrics of polyester/cellulosic and polyester/wool blends have beengaining substantial commercial importance, especially such fabricscontaining wool or wherein the cellulosic is cotton. However, the lowcovering power of typical polyester/ cotton and polyester/wool blendfabrics emphasizes the unevenness of the yarn while all-cotton andall-wool fabrics with yarns of equivalent evenness appear more even dueto the surface cover of the cotton or wool fibers.

It is accordingly an object of this invention to improve the surfacecover of polyester/cellulosic and polyester/ wool blend fabrics.

It is also an object of this invention to provide polyester/cellulosicand polyester/wool blend fabrics having a soft brushed surface and goodsurface cover.

When polyester fiber in staple form is used in polyester/ cellulosic andpolyester/wool blend fabrics, a serious problem with regard to pillingof the polyester at the surface of the fabric may be encountered. Suchpilling, of course, substantially lessens the desirability of thefabric. The pilling is unpleasing in appearance; at times, large pillswill shed from the surface of the fabric, which, of course, isundesirably messy.

Thus, it is a further object of this invention to produce soft,pilling-resistant fabrics of blends comprising polyester staple fibersand cellulosic or wool fibers.

The cellulosic fibers to be used in the blend often will be in stapleform, too. This is because the most common of the cellulosic fibers,cotton, occurs only in staple form and because staple fibers, ascompared with continuous filaments, generally have a softer hand, softersurface, warmer feeling and are found by the consumer to be moreaesthetically pleasing.

Accordingly, it is yet another object of this invention to produce softpilling-resistant fabrics of blends comprising polyester and cellulosicstaple fibers.

Other objects of this invention will be apparent from the followingdetailed description and claims.

In accordance with one aspect of this invention, there .is provided amethod of producing soft, pilling-resistant 3,403,433 Patented Oct. 1,1968 because in subsequent wet processing, such as dyeing, the polyesterfibers remain relatively stable while the cellulosic or wool shrinkssubstantially, thereby offsetting some of the coring effect obtained.The term coring effect, of course, refers to the selective shrinkage andmigration of the polyester fibers in the blend to the center of theyarn. The fabric thus produced will be referred to hereinafter in thespecification and claims as a cored yarn fabric. For the same reasonthat it is preferred to avoid dyeing of the cored yarn fabric, it isalso preferred to avoid mercerization or Sanforization of such fabric.The above-mentioned restraining and heating of the restrained fabricwill hereinafter be referred to as restrained heat setting.

In another aspect of this invention, it is preferred to remove anypolyester fibers remaining at the surface of the heat-set fabric by theuse of singeing. Singeing generally involves the exposure of thesurfaces of the fabric to a flame, whereby the polyester fibersremaining near the surface of the fabric are selectively burned awaybecause the polyester fibers have a lower decomposition point than thecellulosic or wool fibers. Of course, any other source of sufiicientheat could be used, such as heated rolls or plates past which the fabricwould move either near the surface thereof or in contact therewith.

In another aspect of this invention, after the singeing operation, ifemployed, the fabric is brushed for the purpose of further raisingcellulosic or wool to the surface thereof. Preferably after the singeingoperation, but prior to the brushing operation, a brushing softener isapplied to the fabric. The brushing softener may comprise any of thefollowing, alone or in a mixture: anionic, nonionic and cationic steariccompounds, silicone oils, sulfated oils and fats, alkyl quaternaries orsolutions, emulsions or suspensions of'any of the preceding substances,mineral oil emulsions and polyethylene emulsions and the like.Preferably, steam is applied to the fabric during the brushing operationfor the purpose of effecting lubrication between the bristle surfacesand fabric surface.

It is preferred to apply the softener alone for best brushed pileformation. However, a finishing resin may be applied with the softener.Such resins may be applied as a solid, melt, solution, suspension oremulsion and, if thermosetting, the unreacted or partially reactedcomponents of the resin may be so applied and subsequently cured.Typical thermosetting finishing resins or reactant resin componentswhich may be applied are methylol urea, methylated methylol urea,methylol cyclic ethylene urea, methylol melamine, methylated methylolmelamine, polyesters, phenolic formaldehyde, acetone formaldehyde, epoxyresins, melamine resin acid colloid, dirnethylolpropyleneurea,dimethylol-uron-dimethylether and methylol triazone. Typicalthermoplastic resins which may be applied are butadiene/styrene andbutadiene/acrylonitrile copolymers and polymers and copolymers ofacrylate esters, vinyl acetate, vinyl alcohol, vinyl butyral, vinylchloride, vinylidene chloride, styrene, ethylene, propylene, linearester condensates, linear amide condensates, natural rubber and thelike.

If it is desired to incorporate calendering in the fabric finishingoperations, it is preferred to calender after singeing and brushingbecause calendering before brushing flattens the fabric and hinders goodpile formation in brushing. However, the results achieved in terms ofpile formation and pilling performance if the calendering is performedbefore brushing can be improved by low pressure calendering (e.g., silkcalendering) subsequent to the initial calendering and before thebrushing. Silk calendering is generally performed by passing the fabricin sequence between the two nips of a three-bowl calender, the top andbottom bowl (roll) surfaces of which are 3 usually paper and the centerbowl (roll) surface of which is usually metal.

The resin finish is then cured. For this purpose, a conventional loopdryer is particularly suitable. However, any other type oven or dryerwhich would provide adequate dwell time (e.g., a conventional rollercuring oven) would also be satisfactory. Temperature and dwell time are,of course, dependent on the particular resin finish. However, sinceconventional resin finishes are used, conventional curing times andtemperatures for these resins are well known in the art.

Subsequent to all the above steps, the fabric may be conventionallypressed and/ or decated or semi-decated.

The above referred to restrained heat setting is carried out at fromabout 325 to about 425 F., preferably from about 350 to 415 F., for aduration of from about 300 to 5 seconds, preferably from about 60 toabout seconds (temperature and time being correlated inversely).

The above referred to singeing preferably is carried out at a flametemperature of about 2000 to about 4000 F. for a duration of from about0.02 second to 0.08 second (temperature and time being correlatedinversely).

Hinneken boil off and prescouring are conventional and may be performedat conventional temperatures and durations, which, of course depend uponthe specific fabric treated.

The extent of drying of the fabric, subsequent to padding, is preferablyto a moisture content of from about 1 to preferably from about 2 toabout 10%, whereby, the fabric is suitably soft for the subsequentbrushing.

The curing of the finish on the fabric and the decating are performedunder conventional conditions.

The term polyester as used in the specification and claims refers topolyesters of glycols and dibasic acids, particularly glycols of theseries HO(CH ),,OH where n is an integer within the range of 2-10, andthe dibasic acid is one or more of terephthalic acid, isophthalic acid,adipic acid, sebacic acid, dibenzoic acid and the like.

The term cellulosic includes cotton, regenerated cellulose, cross-linkedregenerated cellulose derivatives, sisal, hemp, jute, linen, ramie,tampico and the like.

It is not absolutely necessary to use a tenter frame or other restraintduring the drying; the major purpose of such restraint is to control thefinal fabric dimensions. Whether or not the fabric is restrained duringdrying has no noticeable effect on the results of the subsequentheatsetting operation. The drying temperature is not critical; however,generally temperatures not in excess of about 250 F. are used in orderto avoid any premature coring.

The following examples further illustrate the present invention:

EXAMPLE I A sample of viyella flannel made of 26/1s (i.e., yarn madefrom one end having a cotton count of 26) (19 turns/inch S-twist) of 65%1.5 denier x 1 /2" polyethylene terephthalate staple fibers and 35%combed Pima cotton both in the Warp and in the filling and having a loomcount of 74 ends/inch x 70 picks/inch, the reed width being 50.5" with37 reed dents per inch and 2 ends per dent and the weave being a 2 x 2twill, is treated as follows:

(A) Hinneken boil oil. of the fabric at 200 F. with prescouring boxes at120 F.;

(B) Desizing and scouring of the fabric in a beck;

(C) Union dyeing of the fabric in a beck to a periwinkle shade, usingdisperse dye with carrier for the polyester and fixable direct dyes forthe cotton;

(D) Drying of the fabric with hot air at 250 F.;

(E) Heat setting of the fabric while laterally restrained againstshrinkage on a Famatex tenter pin frame at 400 F. for 20 seconds,holding the dyed width (dyed width is the width of the fabric in acompletely relaxed state after dyeing and subsequent drying;alternatively, dyed width will be referred to as pre-heat set lateraldimension);

4 (F) Thorough singeing of the fabric; (G) Padding of the followingresin finish and fabric softener mixture onto the fabric:

Grams/liter Permafresh LF (dimethyloldihydroxyethylene urea) 60 CatalystW (organic acid complex sold by Sun Chemical Company, Warwick Division)12 Moropol 700 (nitrogen-free nonionic polyethylene emulsion) 15 BufferDCY (dicyandiamid) 4 (H) Drying of the fabric on a tenter clip framewith hot air at 250 F., leaving approximately 5% moisture content;

(I) Brushing of the fabric three times on each side on soft steelbristle brush roll with an open steam pipe attached through which steamis applied to the fabric as it is brushed;

(J) Loop curing of the fabric at 315 F. for four minutes;

(K) Semi-decating of the fabric by the use of a semidecator, withalternate steam and vacuum cycles of from 10 to 60 seconds each.

EXAMPLE II A sample of hopsacking made of 16/1s (15.5 turns per inchZtwist) of 55% 3.0 denier x 2" semi-du1l polyethylene terephthalatestaple and 45% 3.0 denier x 2" semi-dull Corval cross-linked regeneratedcellulose) both in the warp and in the filling (but the filling beingpackage dyed black) and having a loop count of 72 ends/inch X 54picks/inch, the reed width being 50" with 36 reed dents per inch and 2ends per dent and the weave being a 2 x 2 basket weave is treated asfollows:

(A) Hinneken boil off of the fabric at 200 F. 'with prescouring boxes atF.;

(B) Desizing and securing of the fabric in a beck;

(C) Dyeing of warp yarns to ironwood (a medium tan shade) union usingdye carrier for the polyester;

(D) Drying the fabric with hot air at 250 F. to a dyed width of 48";

(E) Heat setting of the fabric on Famatex tenter pin frame at 400 F.,for 20 seconds, holding the dyed width;

(F) Thorough singeing of the fabric at a cotton setting on an IndustrialHeat Engineering Singer of Flame 6, Speed 10;

(G) Pad-ding of the following resin finish and fabric softener onto thefabric:

Grams/liter Aerotex resin M3 (melamine formaldehyde condensate resin) 50Catalyst MX (magnesium chloride) 15 Ahcovel G (cationic softener-fattycarbamide) 15 Triton X-lOO (ethoxylated nonylphenol) 1 (H) Drying of thefabric on a tenter clip frame with hot air at 250 F., leavingapproximately 5% moisture content;

(I) Brushing of the fabric three times on each side on soft steelbristle brush roll with an open steam pipe attached through which steamis applied to the fabric as it is brushed;

(J) Loop curing of the fabric at 320 F. for four minutes;

(K) Silk calendering of the fabric at 5 tons total pressure through bothnips of a three-bowl silk calender, the top and bottom roll surfaces ofwhich are paper and the middle roll surface of which is stainless steel;

(L) Pressing of the fabric on a rotary press at setting 35. (This is anumber in a range of 0 to 60 indicating about medium pressure. It is aregulation of the distance between a stationary pan and a turning roll.The temperature is constant at about 280 F.)

(M) Decating of the fabric.

EXAMPLE III A sample of lawn made of 70/ ls of 65% polyethyleneterephthalate staple and 35% cotton both in the warp and in the fillingand having a greige construction of 88 ends/inch x 76 picks/inch, thegreige width being 40" is treated as follows:

(A) Desizing and scouring of the fabric in a beck (a lawn is not such afabric construction as would tend to crack if not relaxed first; thistype fabric may or may not be boiled off; as a matter of convenience, itwas not; for any particular fabric, whether or not a Hinneken boil offis to be performed is a matter of choice);

(B) Bleaching of the fabric with peroxide in a beck to remove motes;

(C) Dyeing of the fabric in a beck to light union pink shade (using adye carrier for the polyester);

(D) Tenter clip frame drying of the fabric at 37" (1" over dyed wetwidth) with hot air at 250 F.;

(E) Heat setting of the fabric on Famatex tenter pin frame at 415 F. for15 seconds, holding the 37" width;

(F) Singeing of the fabric at a cotton setting on an Industrial HeatEngineering Singer of Flame 6, Speed (G) Silk calendering of the fabricat 5 tons total pressure through both nips of a three-bowl silkcalender, the top and bottom roll surfaces of which are paper and themiddle roll surface of which is stainless steel;

(H) Padding of the following resin finish and fabric softener onto thefabric:

Grams/liter Permafresh LF (dimethyloldihydroxyethylene urea) 60 CatalystW (organic acid complex) 12 Moropol 700 (nitrogen free nonionicpolyethylene emulsion) 15 (I) Drying of the fabric on a tenter pin framewith hot air at 250 F., leaving approximately 5% moisture content;

(I) Brushing of the fabric three times on each side on soft steelbristle brush roll with an open steam pipe attached through which steamis applied to the fabric as it is brushed;

(K) Loop curing of the fabric at 315 F. for four minutes;

(L) Decatizing of the fabric.

EXAMPLE IV A sample of oxford made of 42/ ls (with 24 turns per inch-Ztwist) in the warp and 15/ ls (with 14 turns per inch-Z twist) in thefilling, both of 65% polyethylene terephthalate staple and 35% cotton,the greige width being 48.5 and the weave being a 2 x 1 plain weave istreated as follows:

(A) Desizing and scouring of the fabric in a beck;

(B) Bleaching of the fabric with peroxide in a beck to remove motes;

(C) Dyeing of the fabric in a beck to a mint green union using dyecarrier for the polyester; the dyed width is forty-four inches;

(D) Drying of the fabric on a tenter pin frame at the dyed width withhot air at 250 F.;

(E) Calendering of the fabric by passing each side once through ahydraulic calender operating at 280 F. and 30 tons total pressure to afabric width of 43% inches;

(F) Heat setting of the fabric on a tenter pin frame at 415 F. for 15seconds while held at a forty-five inch width.

(G) Thorough singeing of the fabric at a cotton setting on an IndustrialHeat Engineering Singer of Flame 6, Speed 10;

6 (H) Padding of the fabric with the following resin finish:

(I) Drying of the fabric on a tenter pin frame with hot air at 250 to awidth of 45% inches;

(J) Loop curing of the fabric at 320 F. for three minutes to a width of44 /2 inches;

(K) Brushing of the fabric three times on each side on soft steelbristle brush roll with an open steam pipe attached through which steamis applied to the fabric as it is brushed;

(L) Decatizing of the fabric.

Treatment of the fabric with hot strong caustic solution (15 g./liter)(preferably prior to dyeing so as not to effect the dye and preferablyprior to the heat setting step so as not to reverse the coring effectdue to the greater shrinkage of cotton than polyester when treated withcaustic solution) may be used as an additional and independentanti-pilling measure. Such treatment tends to decrease pilling by partlydegrading the polyester yarn whereby the polyester is weakened so thatpolyester fibers at the yarn surfaces, when rubbed, gradually break awayfrom the surfaces rather than form bunches or balls of tangled fibers onthe surfaces (which bunches or balls are commonly known as pills)However, it is generally found that incorporating a caustic treatmentinto the present selective coring processes gives only a marginalimprovement with regard to the brush and sponge pilling test (ASTMDl37559*T Method C), results which generally cannot justify theconcomitant strength loss; also, excellent random tumble pilling test(ASTM 1375) results, comparable to those achieved by the use of caustictreatment with the present selective coring processes, are achievedwithout the use of caustic and concomitant strength loss.

The following example is illustrative of the effect of an anti-pillingcaustic treatment:

EXAMPLE V A sample of the same fabric that is the starting material inExample I is treated as follows:

(A) Hinneken boil off of the fabric at 200 F. with prescouring boxes at120 F.;

(B) Desizing and scouring in a winch;

(C) Thirty yards of the sample is taken off at this stage and caustictreated on a winch for fifteen minutes with an aqueous sodium hydroxidesolution of 15 grams/liter concentration and at a temperature of C. Boththis thirty-yard portion of the sample and the balance of the sample aretreated alike for comparative purposes as follows:

(D) Union dyeing of the fabric in a beck to a periwinkle shade, usingdisperse dye with carrier for the polyester and fixable direct dyes forthe cotton;

(E) Tenter clip frame drying of the fabric with hot air at 250 F.;

(F) Heat setting of the fabric on a tenter pin frame at 400 F. for 20seconds, holding the dyed width;

(G) Thorough singeing of the fabric;

(H) Padding of the fabric with the following resin composition:

Grams/liter Permafresh LP (dimethyloldihydroxyethylene urea) 60 CatalystW (organic acid complex) l2 Moropol 700 (nitrogen-free nonionicpolyethylene emulsion) 15 Triton X- (ethoxylated nonylphenol) '1 BufferDCY (dicyandiamid) 4 (I) Drying of the fabric on a tenter clip framewith hot air at 250 F. to a moisture content of 5%;

Property No caustic Caustic Thread count (ends/inch x picks/inch) 84 x76 84 x 76 Weight (on/yd?) 4. 53 4. 31 Grab tensile strength (1115.)(ASTM-D39- 75 x 65 53 x 36 59) (breaking strength-grab method) Tearstrength (lbs.) (ASTM-Dl424-59) (Elmendorf method) 4. 7 x 4. 4 2. 5 x 2.Random tumble pilling test (15/30/60 minuteS (ASTM-D1375) 515/ 5/515Brush and sponge pilling test (ASTM-D- 137559T method C) 2 2-3 Samplesof all fabrics to be treated by the processes of the present inventionmay be cross dyed (e.g., cotton 1 to 3% in excess of the pre-heat setdimension during heat setting. When the fabric contains highlyshrinkable polyester, the lateral restraining may be within the samerange as the lateral restraining used for normally shrinkable polyester,but more latitude of choice is permissible: specifically, the fabric maybe allowed to shrink up to about 10% below its pre-heat setting lateraldimension during heat setting while being laterally restrained againstfurther shrinkage; thus, even under such conditions, it is properly saidthat the fabric is laterally restrained against shrinkage. When thefabric contains highly shrinkable polyester, the lateral restraintduring heat setting preferably is such that the percentage to which thelateral dimension of the fabric during heat-setting is maintained aboveor allowed to decrease below the pre-heat setting lateral dimension iswithin the range of from about 3% above to about 5% below the pre-heatsetting lateral dimension.

The following table (Table I) shows the influence of heat setting withminor stretching, after dyeing (experiment Numbers 1 to 5) and beforedyeing (experiment Number 6), followed by singeing alone or with otherprocess steps in sequence, as listed, in accordance with the presentinvention, upon the pilling resistant properties of polyester/ cottonblend yarns:

TABLE I (SS/% polyethlene (SS/35% polyethylene terephthalate/cottonterephthalate/cotton blcnd oxford containing blend oxford containingExperiment Additional fabric processing steps highly Shrinkable normallyshrinkable N0, polyethylene terephthalate polyethylene terephthalatefibers fibers Filling 1 Width (in.) Filling 1 Width (in.)

1 Singeing 1 1 46 2 Singeing, padding softener, brushing.. 4 43% 3 473-.- Singeiug, padding resin, hot calender- 2 41% 1 44% ing, curing. 4Singeing, padding resin, hot calender- 2 41% 1 44 ing, curing, brushing.5 Singeing, silk calendaring, padding 4 42% 1 4 resin, brushing, curing.6 Singeing, padding softener, brushing 3 44% 2-3 47 1 Brush and sponge,after washing of fabric.

black and polyester orange) to facilitate identification of fibercomponents and thus determine fiber migration. Comparison of thecross-dyed fabric samples will show the fabric to become darker in coloras the polyester yarn is selectively cored and to become still darker incolor as residual polyester is signed from the surface and even darkeras the cotton (or other black-dyed cellulosic is brushed to the surface;comparison of yarn samples at these various stages will confirm thatpolyester is selectively cored and removed from the yarn surfaces andthat cellulosic is selectively raised to the yarn surface. By dissolvingcotton from a sample of the fabric before heat setting and dissolvingcotton from another sample of the same fabric after heat setting and bycomparison of the polyester shades of the two samples, which shows themto be the same, it is confirmed that the observed shade changes in theblend fabrics upon heat setting are due to selective coring of thepolyester rather than heat-induced migration of the dye.

The term restrained heat setting as used in the present specificationand claims means heat setting of the fabric while it is laterallyrestrained against shrinkage. Restraining may be accomplished by use ofa tenter frame (pin or clip or any other type), pinch rolls or any otherconventional means for laterally restraining fabric. When the fabriccontains normally shrinkable polyester, it is preferred that the lateralrestraining during heat setting constitute maintaining the fabric at itsinitial (i.e., pre-heat setting) lateral dimension or at lateraldimension of up to about 5% in excess thereof; preferably, the lateraldimension of the fabric is maintained at about It is thus apparent thata highly shrinkable polyestercontaining blend will tend to demonstrategreater pilling resistance than an identically processed normallyshrinkable polyester-containing blend. This apparently is because thecoring effect in the former is greater than in the latter yarns. Highlyshrinkable polyester means polyester filaments which have not beenconventionally heat set during their manufacture and thus will shrink inboiling water substantially more than the 10-l2% which is typical ofconventionally heat set, i.e., normally shrinkable, polyester.

The following table (Table II) shows the effect of shrink-proofing("Sanforize process) preceded or not by mercerization on pillingperformance. The fabrics tested in each of these experiments are oxfordseach having a warp of 88 ends/inch of 50/ ls of 30 turns/inch Z-twist35/ polyethylene terephthalate/cotton yarn. Under the heading FillingYarn, px. means picks/inch and P/ C means polyester/ cotton blend yarn.Under the heading Pilling Test, B & S means 12 minute duration Brush &Sponge Test and RT means 30 minute duration Random Tumble test. Theheadings Original" and Washed mean, respectively, that the fabric wasnot washed after being processed and before being tested and that thefabric was so washed. The fabric processing steps are, of course, listedinchronological order.

Prior to the performance of the listed processing steps, each fabric ineach experiment was heat set while laterally restrained againstshrinkage at 415 F. for 20 seconds. Each singeing and resingeing wasperformed at an Industrial Heat Engineering Singer Setting of Flame 6,Speed 10.

TABLE II Singed and resin Singed, resin finished Singed, resin finished,Mercerized, singed and finished and shrink-prooied reslnged andshrinkshrink-prooted Filling Yam 1 Pilling test proofed Original WashedOriginal Washed Original Washed Original Washed 46 px., /1s 65/35% PIC;polyester is 1.5 B & S 2 2 3 3 2 1 1 1 denier x 1 sta is. RT 5 2 5 5 1-31 1 5 46 px., 30/2s 50/509 P/C; polyester is 1.5 B & S 3-4 3 3 4 1 2 3 3denier x 1% stop RT- 5 5 5 5 5 5 H 5 46 px., 1.5/1's (ES/35% P/C;polyester is 3.0 B & 1 2 4 4 1 1 1 1 denier x 1, 4 staple. RT 5 5 5 5 55 3 5-4 1 In each fabric, warp yarn is 50/ls 30 turnslinchZ twist,65/35% PIC.

The following table (Table III) shows the effect of mercerization onpilling performance. The mercerization consisted of caustic impregnation(4852 TW. concentration) of the fabric on a pad, removal of excesscaustic by squeezing, holding the fabric under filling tension on atenter clip frame and partially washing out the caustic from the fabricwhile under tension, and completing of washing of the fabric in a 6-boxopen width washer with neutralization of the fabric in the last box.Prior to the steps listed in the table, each fabric was heat set at 400F. for seconds while laterally restrained against shrinkage, brushed twotimes on each side with a soft steel bristle brush roll and singed at anIndustrial Heat Engineering Singer Setting of Flame 6, Speed 10. In thetable, the fabric tested is a gabardine having a warp of 132 ends/inchand a fill of 72 picks/inch each of ls of Z-twisted 65/ polyethyleneterephthalate/ cotton yarn.

TABLE III Random tumble Elmendorf Additional processing steps pillingtest tear test (lbs.)

30 min. 60 min. Warp Fill Mercerized and finished 4 34 4. 0 2. 9Finished only 4-5 4 4. 5 2. 8

The following table (Table IV) sets forth pilling and strength data forthe fabric produced in each of the Examples I to IV, above.

With the processes of the present invention it is now possible toproduce pilling-resistant polyester/cellulosic or polyester/wool fiberflannels, sleepwear lawns, soft oxfords for womens wear, suiting fabricswith an all woollike hand and the like.

It will, of course, be understood that the above exampies and tables arenot limitative but merely illustrative of the present invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. Method of producing soft, pilling-resistant fabric of blend yarncomprising polyester staple fibers and fibers selected from the groupconsisting of cellulosics. and wool comprising the steps of restrainingthe fabric and heating said restrained fabric whereby the polyesterstaple fibers shrink and migrate to the center of the yarn.

2. The method of claim 1, wherein said selected fibers comprise acellulosic.

3. The method of claim 1, wherein said selected fibers comprise wool.

4. The method of claim 2, wherein said cellulosic comprises cotton.

5. The method of claim 1, wherein the fabric is dyed prior to saidrestraining and heating steps.

6. The method of claim 1, wherein after said restraining and heatingsteps the fabric is singed so as to remove residual polyester fibersfrom the surface thereof.

7. The method of claim 6, wherein after the singeing step the fabric isbrushed in order to raise additional selected fibers to the surfacethereof.

8. The method of claim 1, wherein said heating step is at a temperaturein the range of from about 325 to about 425 F.

9. The method of claim 7, wherein lubricant is. incorporated with thefabric thereby to facilitate the raising of the selected fibers.

10. The method of claim 9, wherein moisture is applied to serve aslubricant.

11. The method of claim 10, wherein the moisture application isaccomplished by feeding steam through a pipe attachment to the brushes.

12. Method of producing soft, pilling resistant fabric of blend yarncomprising polyester fibers and fibers selected from the groupconsisting of cellulosics and wool comprising the steps of restrainingthe fabric, heating said restrained fabric whereby the polyester staplefibers shrink and migrate to the center of the yarn, applying an aqueouscomposition to said fabric, drying said aqueous composition containingfabric to a moisture content of from about 1 to about 10% based on theweight of the dry fabric, applying lubricant to said dried fabricthereby to facilitate the subsequent raising of the selected fibers, andbrushing said lubricant-containing fabric thereby to raise additionalselected fibers to the surface thereof.

13. The method of claim 12, wherein said selected fibers comprise acellulosic.

14. The method of claim 12, wherein said selected fibers comprise wool.

15. The method of claim 13, wherein said cellulosic comprises cotton.

16. The method of claim 12, wherein said aqueous composition comprisesbrushing softener.

17. The method of claim 12, wherein said aqueous composition comprisesfinishing resin.

18. The method of claim 12, wherein said aqueous composition comprisesfinishing resin and brushing softener.

19. The method of claim 12, wherein said heating step is at atemperature of from about 325 to about 425 F.

References Cited UNITED STATES PATENTS 2,897,042 7/1959 Heils 57-140 X3,006,055 10/1961 Chapin 2619 3,060,551 10/ 1962 Bogaty et al. 28--76 X3,279,163 10/1966 Lulay et a1 57-140 FOREIGN PATENTS 133,874 8/ 1949Australia. 466,070 6/ 1950 Canada.

LOUIS K. RIMRODT, Primary Examiner.

